Tonight the search for answers in that deadly 4th of July boat crash that killed four people in a busy Florida marina. A grim reminder that this can be the most dangerous time for boaters. But there are ways to stay safe. ABC's Alex Perez has the story tonight. Reporter: A celebration ends in tragedy just as the fireworks show wrapped up Friday night. In mime Miami. A deadly collision, one boat runs into another. That driver thrown into the water leaving this gaping hole. It's a tragedy for us to see something like this happen. This is probably the worst accident I have seen in my 11 years. Reporter: The victims all in their 20's. Two killed instantly. And another two died after being thrown into the water. By the crash. Seven injured. The scene so bad, grief counselors called in. To help first responders. A lot of people are affected as what happened. Reporter: Last summer 83 people died during the month of July in boating accidents. In crowded marinas this time of year, big problem? It is a big problem. You have people going into restaurants, docking in areas they shouldn't. Not always easy. Reporter: Safety experts say it's critical to follow basic boating rules. Make sure lighting and sound signals are working properly. Avoid alcohol. Don't exceed maximum passenger capacity. Two years ago a overcrowded yacht sank killing three children. Experts say there are few things you should remember getting on a boat. Always know where the life vests are and make sure there's one vest per person. Always carry your cell phone and remember to tell people where you're going to be. Simple tips that could save your life. Thanks so much. Very important to remember.

This transcript has been automatically generated and may not be 100% accurate.

{"id":24446864,"title":"Boating Tragedy in Miami","duration":"1:47","description":"Three boats collide off Miami in deadly crash as a celebration ends in tragedy.","url":"/WNT/video/boating-tragedy-miami-24446864","section":"WNT","mediaType":"Default"}